1. Field of the Invention
This invention relates generally to a powertrain for a vehicle, and, more particularly, to a powertrain having multiple power sources including an electric motor for driving a set of vehicle wheels.
2. Description of the Prior Art
Hybrid electric powertrains have been developed that include an electric motor and an internal combustion (IC) engine, which can operate independently or in combination depending on the driving conditions, the state of charge of a traction battery, and the power source that most efficiently meets the current power demands imposed by the vehicle operator.
When packaging an electric motor drive unit for a rear axle it is preferable to place the motor drive unit on the rear axle centerline for best packaging efficiency.
To improve operating efficiency and to allow battery charging at zero vehicle speed, clutches or couplers are required in the ERAD unit, such as high speed disconnect clutch and mechanical drive disconnect clutch. The high speed disconnect will improve efficiency, and the mechanical drive disconnect allows battery charging at rest.
A need exists in the industry for a low-cost, hybrid electric powertrain in which operating efficiency is improved and battery charging capability is provided when vehicle speed is zero. A high speed disconnect clutch and mechanical drive disconnect clutch would improve efficiency and permit battery charging when the vehicle is stopped.